Ultimate Fighting Championship (UFC) today announced that former number one heavyweight title contender Shane Carwin will replace an ill Brock Lesnar, taking on Junior dos Santos in the main event of UFC 131 on June 11, 2011, in Vancouver, British Columbia, Canada.

The promotion revealed on a spur of the moment media conference call that Lesnar had a diverticulitis relapse, which forced him off the card, but will not signal the end of his mixed martial arts career.

For the latest on Lesnar and his illness click here, here and here.

While certainly a disappointment, considering dos Santos spent considerable time and energy preparing for Lesnar on the set of The Ultimate Fighter (TUF) 13, fighting for the right to still face division champion Cain Velasquez against a man who shares similar skill and size, has to be somewhat of a relief.

"Cigano" cemented his place among the heavyweight big guns after a string of impressive performances against the likes of former Pride FC star Mirko "Cro Cop" Filipovic at UFC 103, Gilbert Yvel at UFC 108 and most recently against Roy "Big Country" Nelson at UFC 117 last August.

In fact, the Brazilian has enjoyed something of a UFC Cinderella story, being brought in for what was thought to be a squash match against Fabricio Werdum in his 2008 debut. Dos Santos had other plans, knocking out "Vai Cavalo" and forcing the UFC to give him the best the division has to offer, mostly because he's destroyed everyone else worth mentioning in the 265-pound weight class, going undefeated (6-0) with five stoppages.

But can he withstand the powerful wrestling of "The Engineer?"

Carwin was originally scheduled to welcome heavyweight submission specialist Jon Olav Einemo to the Octagon for the first time ever, meaning that he was already prepared to get into a fight a little less than a month from today.

Just not against a Brazilian beast.

Nonethless, Carwin feels that fighting dos Santos to reclaim his title as number one division contender is "where he belongs." It likely won't be a walk in the park, considering Carwin will be be making his return after nearly a year-long layoff following his arm-triangle loss to then heavyweight champion Brock Lesnar.

The big man dominated the first round before his massive muscles could no longer get the oxygen needed to operate properly and gave way. He vowed to return stronger and better than ever, which he was initially set to do at UFC 125 against Roy Nelson.

However, "The Engineer" went under the knife to repair an ailing neck, which forced the promotion to insert "Big Country" into a match up against Frank Mir, instead.

In addition to the re-shuffled main event between dos Santos and Carwin, UFC 131 will feature a middleweight match between wrestling powerhouse Mark Munoz and Brazilian jiu-jitsu ace Demian Maia. Kenny Florian is also slated to make his featherweight debut against wily scrapper Diego Nunes.

As always, stay tuned to BCMMAA.com for any updates to this still-developing fight card.